The somatic sensation is a sensation perceived by the receptors in the superficial layer and deeper tissue of the body. It is divided into tactile cutaneous sensation and deep sensation generated by motor organs such as muscles and tendons. Deep somatic sensation accompanying exercises plays an important part in medical fields such as rehabilitation and surgery, and also sports science. Additionally, it is considered that machines should have the capability of estimating the somatic sensation of the human body for smooth interaction between people and machines.
The first step in estimating the somatic sensation from motions is to estimate the muscle force from motion data. Conventionally, there have been many studies to estimate muscular force from motion data. However, in these studies the muscular force was calculated using the geometrical nature of the motion such as the physiological model of muscles and percentage change of muscular length. They did not consider whether the motion could be realized with the obtained muscular force. A method for calculating the muscular force considering dynamic validness includes the AnyBody Project (J. Rasmussen, M. Damsgaard, E. Suruma, S. T. Christensen, M. de Zee, and V. Vondrak: “AnyBody-a software system for ergonomic optimization,” Fifth World Congress on Structural and Multidisciplinary Optimization, 2003) and studies of the inventors (Y. Nakamura, K. Yamane, I. Suzuki, and Y. Fujita: “Dynamic Computation of Musculoskeletal Human Model Based on Efficient Algorithm for Closed Kinematic Chains,” Proceedings of International Symposium on Adaptive Motion of Animals and Machines, SaP-I-2, 2003). However, they did not consider the physiological validness. The number of muscular tensions physically valid for a single motion is innumerable. However, they are not always physiologically valid. Conventionally, there have been methods for calculating muscular tensions that are satisfactory in either a physical manner or physiological manner, but there has been no method for calculating the muscular tension satisfying the physical and physiological characteristics at the same time.
Patent document: Japanese published unexamined application 2003-339673